import type {
  BranchGraphColumnOption,
  BranchGraphCommandValue,
  CellContext,
  ColorDef,
  FieldDef,
  GridCanvasHelperAPI,
  ListGridAPI,
  MaybePromise,
  MaybePromiseOrUndef,
} from "../../ts-types";
import type { DrawCellInfo, GridInternal } from "../../ts-types-internal";
import { getOrApply, isPromise, obj } from "../../internal/utils";
import { BaseColumn } from "./BaseColumn";
import { BranchGraphStyle } from "../style/BranchGraphStyle";
import { getBranchGraphColumnStateId } from "../../internal/symbolManager";

const _ = getBranchGraphColumnStateId();

type Timelines = { timeline: BranchPoint[][]; branches: string[] };

function getAllColumnData<T>(
  grid: ListGridAPI<T>,
  field: FieldDef<T>,
  callback: (allData: BranchGraphCommandValue[]) => void
): void {
  const { dataSource } = grid;
  const allData: BranchGraphCommandValue[] = [];
  let promise;
  for (let index = 0; index < dataSource.length; index++) {
    const data = dataSource.getField(
      index,
      field
    ) as MaybePromiseOrUndef<BranchGraphCommandValue>;
    if (isPromise(data)) {
      const dataIndex = allData.length;
      allData.push(undefined);
      if (!promise) {
        promise = data.then((d) => {
          allData[dataIndex] = d;
        });
      } else {
        promise = promise
          .then(() => data)
          .then((d) => {
            allData[dataIndex] = d;
          });
      }
    } else {
      allData.push(data);
    }
  }

  if (promise) {
    promise.then(() => callback(allData));
  } else {
    callback(allData);
  }
}

class BranchLine {
  readonly fromIndex?: number;
  toIndex?: number;
  readonly colorIndex: number;
  readonly point?: BranchPoint;
  constructor({
    fromIndex,
    toIndex,
    colorIndex,
    point,
  }: {
    fromIndex?: number;
    toIndex?: number;
    colorIndex: number;
    point?: BranchPoint;
  }) {
    this.fromIndex = fromIndex;
    this.toIndex = toIndex;
    this.colorIndex = colorIndex;
    this.point = point;
  }
}
class BranchPoint {
  readonly index: number;
  readonly commit: boolean;
  lines: BranchLine[];
  readonly tag?: string;
  constructor({
    index,
    commit = false,
    lines = [],
    tag,
  }: {
    index: number;
    commit?: boolean;
    lines?: BranchLine[];
    tag?: string;
  }) {
    this.index = index;
    this.commit = commit;
    this.lines = lines;
    this.tag = tag;
  }
  static mergeLines(lines: BranchLine[]): BranchLine[] {
    const result = lines.filter(
      (l) => l.fromIndex != null && l.toIndex != null
    );

    const fromList = lines.filter(
      (l) => l.fromIndex != null && l.toIndex == null
    );
    const toList = lines.filter(
      (l) => l.fromIndex == null && l.toIndex != null
    );

    fromList.forEach((f) => {
      for (let i = 0; i < toList.length; i++) {
        const t = toList[i];
        if (t.point) {
          continue;
        }
        if (f.colorIndex === t.colorIndex) {
          f.toIndex = t.toIndex;
          toList.splice(i, 1);
          break;
        }
      }

      result.push(f);
    });

    return result.concat(toList);
  }
  static merge(a: BranchPoint, b: BranchPoint): BranchPoint {
    if (!a) {
      return b;
    }
    return new BranchPoint({
      index: a.index,
      commit: a.commit || b.commit,
      lines: BranchPoint.mergeLines(a.lines.concat(b.lines)),
      tag: a.tag || b.tag,
    });
  }
}

function joinLine(timeline: BranchPoint[][], branchIndex: number): boolean {
  const reverse = [...timeline].reverse();
  for (let i = 0; i < reverse.length; i++) {
    const f = reverse[i][branchIndex];
    if (f) {
      f.lines = BranchPoint.mergeLines(
        f.lines.concat([
          new BranchLine({
            toIndex: branchIndex,
            colorIndex: branchIndex,
          }),
        ])
      );

      for (let j = 0; j < i; j++) {
        const tl = reverse[j];
        tl[branchIndex] = new BranchPoint({
          index: branchIndex,
          lines: [
            new BranchLine({
              fromIndex: branchIndex,
              toIndex: branchIndex,
              colorIndex: branchIndex,
            }),
          ],
        });
      }
      return true;
    }
  }
  return false;
}

function branch(
  { timeline, branches }: Timelines,
  from: string | null,
  to: string
): BranchPoint | null {
  const fromIndex = from != null ? branches.indexOf(from) : -1;
  let toIndex = branches.indexOf(to);
  if (toIndex < 0) {
    toIndex = branches.length;
    branches.push(to);
  }

  function findBranchRootIndex(): number {
    for (let index = timeline.length - 1; index >= 0; index--) {
      const tl = timeline[index];
      const from = tl[fromIndex];
      if (from && from.commit) {
        return index;
      }
    }
    return -1;
  }

  if (fromIndex < 0) {
    return new BranchPoint({
      index: toIndex,
    });
  } else {
    const fromTargetIndex = findBranchRootIndex();
    if (fromTargetIndex === -1) {
      return null;
    }
    const branchTargetFromIndex = fromTargetIndex + 1;
    const branchPoint = new BranchPoint({
      index: toIndex,
      lines: [
        new BranchLine({
          fromIndex,
          colorIndex: toIndex,
        }),
      ],
    });
    let point;
    let result = null;
    if (branchTargetFromIndex < timeline.length) {
      const targetLine = timeline[branchTargetFromIndex];
      point = targetLine[toIndex] = BranchPoint.merge(
        targetLine[toIndex],
        branchPoint
      );
    } else {
      point = branchPoint;
      result = branchPoint;
    }
    const from = timeline[fromTargetIndex][fromIndex];
    from.lines = BranchPoint.mergeLines(
      from.lines.concat([
        new BranchLine({
          toIndex,
          colorIndex: toIndex,
          point,
        }),
      ])
    );
    return result;
  }
}

function commit(
  { timeline, branches }: Timelines,
  name: string
): BranchPoint | null {
  const index = branches.indexOf(name);
  if (index < 0) {
    return null;
  }
  const result = new BranchPoint({
    index,
    commit: true,
  });

  if (joinLine(timeline, index)) {
    result.lines = BranchPoint.mergeLines(
      result.lines.concat([
        new BranchLine({
          fromIndex: index,
          colorIndex: index,
        }),
      ])
    );
  }
  return result;
}

function commitTag(
  { branches }: Timelines,
  name: string,
  tag: string
): BranchPoint {
  let index = branches.indexOf(name);
  if (index < 0) {
    index = branches.length;
    branches.push(name);
  }
  return new BranchPoint({
    index,
    tag,
  });
}

function commitMerge(
  { timeline, branches }: Timelines,
  from: string,
  to: string
): BranchPoint {
  const fromIndex = branches.indexOf(from);
  const toIndex = branches.indexOf(to);
  if (toIndex < 0 || fromIndex < 0) {
    return new BranchPoint({
      index: toIndex,
      commit: true,
    });
  }
  const result = new BranchPoint({
    index: toIndex,
    commit: true,
    lines: [
      new BranchLine({
        fromIndex,
        colorIndex: fromIndex,
      }),
      new BranchLine({
        fromIndex: toIndex,
        colorIndex: toIndex,
      }),
    ],
  });
  const fromList = [...timeline];
  const fromTargetLine = fromList.pop();
  if (fromTargetLine) {
    fromTargetLine[fromIndex] = BranchPoint.merge(
      fromTargetLine[fromIndex],
      new BranchPoint({
        index: toIndex,
        lines: [
          new BranchLine({
            toIndex,
            colorIndex: fromIndex,
          }),
        ],
      })
    );
  }

  if (joinLine(fromList, fromIndex) && fromTargetLine) {
    fromTargetLine[fromIndex].lines = BranchPoint.mergeLines(
      fromTargetLine[fromIndex].lines.concat([
        new BranchLine({
          fromIndex,
          colorIndex: fromIndex,
        }),
      ])
    );
  }
  joinLine(timeline, toIndex);

  return result;
}

function calcCommand(info: Timelines, command: BranchGraphCommandValue): void {
  const { timeline } = info;
  const timelineData: BranchPoint[] = [];
  // const last = timeline.length > 0 ? timeline[timeline.length - 1] : null;
  const commands = Array.isArray(command) ? command : [command];
  commands.forEach((cmd) => {
    if (!cmd) {
      return;
    }
    let point;
    if (cmd.command === "branch") {
      const from = obj.isObject(cmd.branch) ? cmd.branch.from : null;
      const to = obj.isObject(cmd.branch) ? cmd.branch.to : cmd.branch;
      point = branch(info, from, to);
    } else if (cmd.command === "commit") {
      const { branch } = cmd;
      point = commit(info, branch);
    } else if (cmd.command === "merge") {
      const { from, to } = cmd.branch;
      point = commitMerge(info, from, to);
    } else if (cmd.command === "tag") {
      const { branch, tag } = cmd;
      point = commitTag(info, branch, tag);
    }
    if (point && point.index > -1) {
      timelineData[point.index] = BranchPoint.merge(
        timelineData[point.index],
        point
      );
    }
  });
  timeline.push(timelineData);
}

function calcBranchesInfo<T>(
  start: "top" | "bottom",
  grid: ListGridAPI<T>,
  field: FieldDef<T>
): Timelines {
  const result = {
    branches: [],
    timeline: [],
  };
  getAllColumnData(grid, field, (data) => {
    if (start !== "top") {
      data = [...data].reverse();
    }
    data.forEach((command) => {
      calcCommand(result, command);
    });
  });
  return result;
}

function calcBranchXPoints(
  ctx: CanvasRenderingContext2D,
  left: number,
  width: number,
  radius: number,
  branches: string[],
  timeline: BranchPoint[][]
): number[] {
  let w = Math.max(width / branches.length + 1, 5);
  timeline.forEach((tl) => {
    tl.forEach((p, index) => {
      if (index <= 0) {
        // 計算の意味が無い
        return;
      }
      if (p.tag) {
        const textWidth = ctx.measureText(p.tag).width;
        if (w * index + radius * 2 + 4 + textWidth > width) {
          w = Math.max((width - radius * 2 - 4 - textWidth) / index, 5);
        }
      }
    });
  });
  const result: number[] = [];
  let x = left;
  branches.forEach(() => {
    result.push(Math.ceil(x + radius));
    x += w;
  });
  return result;
}

function renderMerge<T>(
  grid: ListGridAPI<T>,
  ctx: CanvasRenderingContext2D,
  x: number,
  y: number,
  upLineIndex: number | undefined,
  downLineIndex: number | undefined,
  colorIndex: number,
  {
    branchXPoints,
    // margin,
    branchColors,
    branchLineWidth,
    mergeStyle,
  }: {
    branchXPoints: number[];
    margin: number;
    branchColors: ColorDef | ((name: string, index: number) => ColorDef);
    branchLineWidth: number;
    mergeStyle: "straight" | "bezier";
  },
  {
    // width,
    col,
    row,
    branches,
  }: {
    width: number;
    col: number;
    row: number;
    branches: string[];
  }
): void {
  if (upLineIndex != null || downLineIndex != null) {
    ctx.strokeStyle = getOrApply(
      branchColors,
      branches[colorIndex],
      colorIndex
    );
    ctx.lineWidth = branchLineWidth;
    ctx.lineCap = "round";
    ctx.beginPath();

    if (upLineIndex != null) {
      const upX = branchXPoints[upLineIndex];
      const upRect = grid.getCellRelativeRect(col, row - 1);
      const upY = upRect.top + upRect.height / 2;
      ctx.moveTo(upX, upY);
      if (mergeStyle === "bezier") {
        ctx.bezierCurveTo(upX, (y + upY) / 2, x, (y + upY) / 2, x, y);
      } else {
        ctx.lineTo(x, y);
      }
    } else {
      ctx.moveTo(x, y);
    }

    if (downLineIndex != null) {
      const downX = branchXPoints[downLineIndex];
      const downRect = grid.getCellRelativeRect(col, row + 1);
      const downY = downRect.top + downRect.height / 2;
      if (mergeStyle === "bezier") {
        ctx.bezierCurveTo(
          x,
          (y + downY) / 2,
          downX,
          (y + downY) / 2,
          downX,
          downY
        );
      } else {
        ctx.lineTo(downX, downY);
      }
    }

    ctx.stroke();
  }
}

/**
 * BranchGraphColumn
 *
 * Data commands
 * - master branch or orphan branch
 *
 * ```js
 * {
 * 	command: 'branch',
 * 	branch: 'branch name A',
 * }
 * ```
 *
 * - commit
 *
 * ```js
 * {
 * 	command: 'commit',
 * 	branch: 'branch name A'
 * }
 * ```
 *
 * - branch
 *
 * ```js
 * {
 * 	command: 'branch',
 * 	branch: {
 * 		from: 'branch name A',
 * 		to: 'branch name B'
 * 	}
 * }
 * ```
 *
 * - merge
 *
 * ```js
 * {
 * 	command: 'merge',
 * 	branch: {
 * 		from: 'branch name B',
 * 		to: 'branch name A'
 * 	}
 * }
 * ```
 *
 * - tag
 *
 * ```js
 * {
 * 	command: 'tag',
 * 	branch: 'branch name A',
 * 	tag: 'tag name'
 * }
 * ```
 *
 * @memberof cheetahGrid.columns.type
 */
export class BranchGraphColumn<T> extends BaseColumn<T> {
  private _start: "top" | "bottom";
  private _cache: boolean;
  constructor(option: BranchGraphColumnOption = {}) {
    super(option);
    this._start = option.start || "bottom";
    this._cache = option.cache != null ? option.cache : false;
  }
  get StyleClass(): typeof BranchGraphStyle {
    return BranchGraphStyle;
  }
  clearCache(grid: ListGridAPI<T>): void {
    const internal = grid as GridInternal<T>;
    delete internal[_];
  }
  onDrawCell(
    cellValue: MaybePromise<unknown>,
    info: DrawCellInfo<T>,
    context: CellContext,
    grid: GridInternal<T>
  ): void | Promise<void> {
    if (this._cache) {
      const state = grid[_] || (grid[_] = new Map());
      const { col, row } = context;
      const field = grid.getField(col, row) as FieldDef<T>;
      if (!state.has(field)) {
        state.set(field, calcBranchesInfo(this._start, grid, field));
      }
    }
    return super.onDrawCell(cellValue, info, context, grid);
  }
  clone(): BranchGraphColumn<T> {
    return new BranchGraphColumn(this);
  }
  get start(): "top" | "bottom" {
    return this._start;
  }
  get cache(): boolean {
    return this._cache;
  }
  drawInternal(
    _value: unknown,
    context: CellContext,
    style: BranchGraphStyle,
    helper: GridCanvasHelperAPI,
    grid: GridInternal<T>,
    { drawCellBase }: DrawCellInfo<T>
  ): void {
    const { col, row } = context;
    const field = grid.getField(col, row) as FieldDef<T>;
    const { timeline, branches } =
      (this._cache ? grid[_]?.get(field) : null) ??
      calcBranchesInfo(this._start, grid, field);

    const {
      upLineIndexKey,
      downLineIndexKey,
    }: {
      upLineIndexKey: "fromIndex" | "toIndex";
      downLineIndexKey: "fromIndex" | "toIndex";
    } =
      this._start !== "top"
        ? { upLineIndexKey: "toIndex", downLineIndexKey: "fromIndex" }
        : { upLineIndexKey: "fromIndex", downLineIndexKey: "toIndex" };
    const data =
      this._start !== "top"
        ? timeline[timeline.length - (row - grid.frozenRowCount) - 1]
        : timeline[row - grid.frozenRowCount];

    const {
      branchColors,
      branchLineWidth,
      circleSize,
      mergeStyle,
      margin,
      bgColor,
      visibility,
    } = style;
    if (bgColor) {
      drawCellBase({
        bgColor,
      });
    }
    if (visibility === "hidden") {
      return;
    }

    const rect = context.getRect();
    const radius = circleSize / 2;
    const width = rect.width - margin * 2;

    helper.drawWithClip(context, (ctx) => {
      ctx.textAlign = "left";
      ctx.textBaseline = "middle";
      const branchXPoints = calcBranchXPoints(
        ctx,
        rect.left + margin,
        width,
        radius,
        branches,
        timeline
      );

      const y = rect.top + rect.height / 2;

      // draw join lines
      data
        .map((point, index) =>
          point
            ? point.lines.map((line) => ({
                colorIndex: line.colorIndex,
                upLineIndex: line[upLineIndexKey],
                downLineIndex: line[downLineIndexKey],
                pointIndex: index,
              }))
            : []
        )
        .reduce((p, c) => p.concat(c), []) // flatMap
        // order of overlap
        .sort((a, b) => b.colorIndex - a.colorIndex)
        .forEach((line) => {
          const x = branchXPoints[line.pointIndex];
          renderMerge(
            grid,
            ctx,
            x,
            y,
            line.upLineIndex,
            line.downLineIndex,
            line.colorIndex,
            {
              margin,
              branchXPoints,
              branchLineWidth,
              branchColors,
              mergeStyle,
            },
            {
              width,
              col,
              row,
              branches,
            }
          );
        });
      // draw commit points
      data.forEach((p, index) => {
        if (p && p.commit) {
          const x = branchXPoints[index];
          ctx.fillStyle = getOrApply(branchColors, branches[index], index);
          ctx.beginPath();
          ctx.arc(x, y, radius, 0, Math.PI * 2, true);
          ctx.fill();
          ctx.closePath();
        }
      });
      // draw tags
      data.forEach((p, index) => {
        if (p && p.tag) {
          ctx.fillStyle = getOrApply(branchColors, branches[index], index);
          ctx.fillText(p.tag, branchXPoints[index] + radius + 4, y);
        }
      });
    });
  }
}