package differ

import (
	"github.com/hashicorp/terraform/internal/command/jsonformat/computed"
	"github.com/hashicorp/terraform/internal/command/jsonformat/computed/renderers"
	"github.com/hashicorp/terraform/internal/command/jsonprovider"
	"github.com/hashicorp/terraform/internal/plans"
)

func (change Change) ComputeDiffForBlock(block *jsonprovider.Block) computed.Diff {
	if sensitive, ok := change.checkForSensitiveBlock(block); ok {
		return sensitive
	}

	if unknown, ok := change.checkForUnknownBlock(block); ok {
		return unknown
	}

	current := change.getDefaultActionForIteration()

	blockValue := change.asMap()

	attributes := make(map[string]computed.Diff)
	for key, attr := range block.Attributes {
		childValue := blockValue.getChild(key)
		childChange := childValue.ComputeDiffForAttribute(attr)
		if childChange.Action == plans.NoOp && childValue.Before == nil && childValue.After == nil {
			// Don't record nil values at all in blocks.
			continue
		}

		attributes[key] = childChange
		current = compareActions(current, childChange.Action)
	}

	blocks := renderers.Blocks{
		SingleBlocks: make(map[string]computed.Diff),
		ListBlocks:   make(map[string][]computed.Diff),
		SetBlocks:    make(map[string][]computed.Diff),
		MapBlocks:    make(map[string]map[string]computed.Diff),
	}

	for key, blockType := range block.BlockTypes {
		childValue := blockValue.getChild(key)

		switch NestingMode(blockType.NestingMode) {
		case nestingModeSet:
			diffs, action := childValue.computeBlockDiffsAsSet(blockType.Block)
			if action == plans.NoOp && childValue.Before == childValue.After {
				// Don't record nil values in blocks.
				continue
			}
			for _, diff := range diffs {
				blocks.AddSetBlock(key, diff)
			}
			current = compareActions(current, action)
		case nestingModeList:
			diffs, action := childValue.computeBlockDiffsAsList(blockType.Block)
			if action == plans.NoOp && childValue.Before == childValue.After {
				// Don't record nil values in blocks.
				continue
			}
			for _, diff := range diffs {
				blocks.AddListBlock(key, diff)
			}
			current = compareActions(current, action)
		case nestingModeMap:
			diffs, action := childValue.computeBlockDiffsAsMap(blockType.Block)
			if action == plans.NoOp && childValue.Before == childValue.After {
				// Don't record nil values in blocks.
				continue
			}
			for dKey, diff := range diffs {
				blocks.AddMapBlock(key, dKey, diff)
			}
			current = compareActions(current, action)
		case nestingModeSingle, nestingModeGroup:
			diff := childValue.ComputeDiffForBlock(blockType.Block)
			if diff.Action == plans.NoOp && childValue.Before == childValue.After {
				// Don't record nil values in blocks.
				continue
			}
			blocks.AddSingleBlock(key, diff)
			current = compareActions(current, diff.Action)
		default:
			panic("unrecognized nesting mode: " + blockType.NestingMode)
		}
	}

	return computed.NewDiff(renderers.Block(attributes, blocks), current, change.replacePath())
}