import { aiOp } from '../runtime/AiLog';
import { AiActionKind } from '../types/AiTypes';
import { AiShovelPolicyType } from '../runtime/AiBattlePersonality';
import { AiBoardProbe } from './AiBoardProbe';
import type { MapGrid } from '../../map/legacy/MapGrid';
import { MapCellKind } from 'db://assets/mx/module/merge';
import type { AiPlannerContext, AiPlannedAction } from '../types/AiTypes';

/** 需求 6.2 铲子使用策略 */
export class AiShovelPlanner {
    private readonly _probe = new AiBoardProbe();

    /**
     * 尝试规划一步铲子动作。
     * @param ctx 决策上下文
     */
    plan(ctx: AiPlannerContext): AiPlannedAction | null {
        const slotIndex = this._probe.findShovelSlotIndex(ctx.bagSession);
        if (slotIndex < 0) return null;
        const digs = this._probe.listEmptyDigGrids(ctx.bagSession, ctx.map);
        if (digs.length <= 0) return null;
        const pick = this._pickDig(ctx, digs);
        if (!pick) return null;
        aiOp(
            `铲子规划 policy=${ctx.personality.shovelPolicy}`
            + ` digCandidates=${digs.length} pick=map[${pick.Index}] rc=(${pick.Row},${pick.Col})`
            + ` walk=${pick.isCanWalk} dig=${pick.isCanBeDig}`
            + ` score=${this._type3Score(ctx, pick)}`,
        );
        return {
            kind: AiActionKind.Shovel,
            merge: {
                source: { kind: 'bag', slotIndex },
                target: { kind: 'map', gridIndex: pick.Index },
            },
        };
    }

    /**
     * 按本局铲子类型选挖格。
     * @param ctx 上下文
     * @param digs 候选挖格
     */
    private _pickDig(ctx: AiPlannerContext, digs: MapGrid[]): MapGrid | null {
        const policy = ctx.personality.shovelPolicy;
        if (policy === AiShovelPolicyType.Type1) {
            let x = (Math.floor(Number(ctx.profile.seed) || 0) >>> 0) || 1;
            x ^= x << 13;
            x ^= x >>> 17;
            x ^= x << 5;
            const idx = (x >>> 0) % digs.length;
            return digs[idx] ?? null;
        }
        if (policy === AiShovelPolicyType.Type2) {
            // 先扩已开岛 / 纯 Dig，再贴邻
            let best: MapGrid | null = null;
            let bestScore = -1e99;
            for (let i = 0; i < digs.length; i++) {
                const dig = digs[i];
                let score = 0;
                if (this._hasOpenedNeighbor(ctx, dig)) score += 100000;
                score += this._countWalkNeighbors(ctx, dig) * 1000;
                if (score > bestScore) {
                    bestScore = score;
                    best = dig;
                }
            }
            return best;
        }
        // Type3 贴路：可走邻接中优先「靠已开 Put / 靠中部」，禁止总挖地图顶边 Dig 条
        return this._pickType3AlongPath(ctx, digs);
    }

    /**
     * 贴路选挖：优先贴已开 Put；其次可走邻接候选；避免固定扫到顶边 Dig。
     * @param ctx 上下文
     * @param digs 全部空挖格
     */
    private _pickType3AlongPath(ctx: AiPlannerContext, digs: MapGrid[]): MapGrid | null {
        let best: MapGrid | null = null;
        let bestScore = -1e99;
        for (let i = 0; i < digs.length; i++) {
            const dig = digs[i];
            const score = this._type3Score(ctx, dig);
            if (score > bestScore) {
                bestScore = score;
                best = dig;
            }
        }
        return best;
    }

    /**
     * Type3 挖格分：贴已开 Put ≫ 可走邻接 ≫ 靠河；边条 Dig 降权。
     * dig+putText 双标已按可放置优先剔除，不会进入候选。
     * @param ctx 上下文
     * @param dig 候选
     */
    private _type3Score(ctx: AiPlannerContext, dig: MapGrid): number {
        let score = 0;
        if (this._hasOpenedNeighbor(ctx, dig)) score += 100000;
        score += this._countWalkNeighbors(ctx, dig) * 1000;
        // 顶/底边 Dig 降权，避免连续铲开整条边 Dig 后把塔摆到地图外缘
        const maxRow = Math.max(0, (ctx.map.mapRows | 0) - 1);
        if (dig.Row <= 0 || dig.Row >= maxRow) score -= 50000;
        score += dig.Row * 10;
        return score;
    }

    private _hasOpenedNeighbor(ctx: AiPlannerContext, dig: MapGrid): boolean {
        const grids = ctx.map.mapGrids;
        if (!Array.isArray(grids)) return false;
        for (let i = 0; i < grids.length; i++) {
            const mg = grids[i];
            if (!mg?.node?.isValid) continue;
            if (Math.abs(mg.Row - dig.Row) + Math.abs(mg.Col - dig.Col) !== 1) continue;
            if (ctx.bagSession.merge.map.getCellKind(mg.Index) === MapCellKind.Put) return true;
            if (ctx.bagSession.merge.map.hasTile(mg.Index)) return true;
        }
        return false;
    }

    private _countWalkNeighbors(ctx: AiPlannerContext, dig: MapGrid): number {
        const grids = ctx.map.mapGrids;
        if (!Array.isArray(grids)) return 0;
        let n = 0;
        for (let i = 0; i < grids.length; i++) {
            const mg = grids[i];
            if (!mg?.node?.isValid) continue;
            if (Math.abs(mg.Row - dig.Row) + Math.abs(mg.Col - dig.Col) !== 1) continue;
            if (mg.isCanWalk) n++;
        }
        return n;
    }
}