class BuildingSystem {
    constructor(scene) {
        this.scene = scene;
        this.isBuildMode = false;
        this.selectedBuilding = 'fence'; // fence, wall, house

        this.buildingsData = {
            fence: { name: 'Fence', cost: { wood: 2 }, w: 1, h: 1 },
            wall: { name: 'Stone Wall', cost: { stone: 2 }, w: 1, h: 1 },
            house: { name: 'House', cost: { wood: 20, stone: 20, gold: 50 }, w: 1, h: 1 }, // Visual is bigger but anchor is 1 tile
            barn: { name: 'Barn', cost: { wood: 50, stone: 10 }, w: 1, h: 1 },
            silo: { name: 'Silo', cost: { wood: 30, stone: 30 }, w: 1, h: 1 }
        };

        // Textures init
        if (!this.scene.textures.exists('struct_fence')) TextureGenerator.createStructureSprite(this.scene, 'struct_fence', 'fence');
        if (!this.scene.textures.exists('struct_wall')) TextureGenerator.createStructureSprite(this.scene, 'struct_wall', 'wall');
        if (!this.scene.textures.exists('struct_house')) TextureGenerator.createStructureSprite(this.scene, 'struct_house', 'house');
        if (!this.scene.textures.exists('struct_barn')) TextureGenerator.createStructureSprite(this.scene, 'struct_barn', 'barn');
        if (this.scene.textures.exists('struct_silo')) TextureGenerator.createStructureSprite(this.scene, 'struct_silo', 'silo');
        // House Lv2 Texture
        TextureGenerator.createStructureSprite(this.scene, 'struct_house_lv2', 'house_lv2');
    }

    toggleBuildMode() {
        this.isBuildMode = !this.isBuildMode;
        console.log(`🔨 Build Mode: ${this.isBuildMode}`);

        // Update UI
        const uiScene = this.scene.scene.get('UIScene');
        if (uiScene) {
            uiScene.toggleBuildMenu(this.isBuildMode);
        }
    }

    selectBuilding(type) {
        if (this.buildingsData[type]) {
            this.selectedBuilding = type;
            console.log(`🔨 Selected: ${this.selectedBuilding}`);

            // UI feedback?
            const uiScene = this.scene.scene.get('UIScene');
            if (uiScene) uiScene.updateBuildSelection(type);
        }
    }

    tryBuild(gridX, gridY) {
        if (!this.isBuildMode) return false;

        const building = this.buildingsData[this.selectedBuilding];
        const inv = this.scene.inventorySystem;
        const terrain = this.scene.terrainSystem;

        // 1. Check Cost
        if (building.cost.wood) {
            if (!inv.hasItem('wood', building.cost.wood)) {
                console.log('❌ Not enough Wood!');
                this.showFloatingText('Need Wood!', gridX, gridY, '#FF0000');
                return true; // We handled the click, even if failed
            }
        }
        if (building.cost.stone) {
            if (!inv.hasItem('stone', building.cost.stone)) {
                console.log('❌ Not enough Stone!');
                this.showFloatingText('Need Stone!', gridX, gridY, '#FF0000');
                return true;
            }
        }
        if (building.cost.gold) {
            if (inv.gold < building.cost.gold) {
                console.log('❌ Not enough Gold!');
                this.showFloatingText('Need Gold!', gridX, gridY, '#FF0000');
                return true;
            }
        }

        // 2. Check Space
        const tile = terrain.getTile(gridX, gridY);
        if (!tile || tile.type === 'water' || tile.hasDecoration || tile.hasCrop || tile.hasBuilding) {
            console.log('❌ Space occupied!');
            this.showFloatingText('Occupied!', gridX, gridY, '#FF0000');
            return true;
        }

        // 3. Consume Resources
        if (building.cost.wood) inv.removeItem('wood', building.cost.wood);
        if (building.cost.stone) inv.removeItem('stone', building.cost.stone);
        if (building.cost.gold) {
            inv.gold -= building.cost.gold;
            inv.updateUI();
        }

        // 4. Place Building
        // Using decorations layer for now
        const structType = `struct_${this.selectedBuilding}`;
        terrain.addDecoration(gridX, gridY, structType);

        // Assume success if no error (addDecoration checks internally but doesn't return value easily, but we checked space before)
        {
            this.showFloatingText(`Built ${building.name}!`, gridX, gridY, '#00FF00');

            // Build Sound
            if (this.scene.soundManager) {
                this.scene.soundManager.playBuild();
            }

            // Quest Tracking
            if (this.scene.questSystem) {
                this.scene.questSystem.trackAction(`build_${this.selectedBuilding}`);
            }
        }

        return true;
    }

    tryUpgrade(gridX, gridY) {
        const terrain = this.scene.terrainSystem;
        const decKey = `${gridX},${gridY}`;
        const decor = terrain.decorationsMap.get(decKey);

        if (!decor) return false;

        // Check if House Lv1
        if (decor.type === 'struct_house') {
            const cost = { wood: 100, stone: 50, gold: 100 };
            const inv = this.scene.inventorySystem;

            // Check Resources
            if (!inv.hasItem('wood', cost.wood) || !inv.hasItem('stone', cost.stone) || inv.gold < cost.gold) {
                this.showFloatingText('Upgrade Cost: 100 Wood, 50 Stone, 100G', gridX, gridY, '#FF4444');
                return true;
            }

            // Pay
            inv.removeItem('wood', cost.wood);
            inv.removeItem('stone', cost.stone);
            inv.gold -= cost.gold;
            inv.updateUI();

            // Perform Upgrade
            terrain.removeDecoration(gridX, gridY);
            terrain.addDecoration(gridX, gridY, 'struct_house_lv2'); // Re-add Lv2

            this.showFloatingText('HOUSE CRADED! (Lv. 2)', gridX, gridY, '#00FFFF');
            if (this.scene.soundManager) this.scene.soundManager.playSuccess();

            return true;
        }

        return false;
    }

    showFloatingText(text, gridX, gridY, color) {
        const iso = new IsometricUtils(48, 24);
        const pos = iso.toScreen(gridX, gridY);
        const popup = this.scene.add.text(
            pos.x + this.scene.terrainOffsetX,
            pos.y + this.scene.terrainOffsetY - 40,
            text,
            { fontSize: '14px', fill: color, stroke: '#000', strokeThickness: 3 }
        ).setOrigin(0.5);
        this.scene.tweens.add({ targets: popup, y: popup.y - 30, alpha: 0, duration: 2000, onComplete: () => popup.destroy() });
    }
}