package tools

import (
	"context"
	"strconv"
	"strings"

	"github.com/modelcontextprotocol/go-sdk/mcp"

	"git.warky.dev/wdevs/amcs/internal/store"
	thoughttypes "git.warky.dev/wdevs/amcs/internal/types"
)

type ThoughtLearningLinksTool struct {
	store *store.DB
}

type LinkThoughtLearningInput struct {
	ThoughtID  string `json:"thought_id" jsonschema:"UUID of the thought to link"`
	LearningID int64  `json:"learning_id" jsonschema:"numeric id of the learning to link"`
	Relation   string `json:"relation,omitempty" jsonschema:"relationship label, e.g. source, derived_from, related; defaults to source"`
}

type LinkThoughtLearningOutput struct {
	Linked bool `json:"linked"`
}

type UnlinkThoughtLearningInput struct {
	ThoughtID  string `json:"thought_id" jsonschema:"UUID of the thought"`
	LearningID int64  `json:"learning_id" jsonschema:"numeric id of the learning"`
}

type UnlinkThoughtLearningOutput struct {
	Unlinked bool `json:"unlinked"`
}

type GetThoughtLearningsInput struct {
	ThoughtID string `json:"thought_id" jsonschema:"UUID of the thought"`
}

type GetThoughtLearningsOutput struct {
	Learnings []thoughttypes.LinkedLearning `json:"learnings"`
}

type GetLearningThoughtsInput struct {
	LearningID int64 `json:"learning_id" jsonschema:"numeric id of the learning"`
}

type GetLearningThoughtsOutput struct {
	Thoughts []thoughttypes.LinkedLearningThought `json:"thoughts"`
}

func NewThoughtLearningLinksTool(db *store.DB) *ThoughtLearningLinksTool {
	return &ThoughtLearningLinksTool{store: db}
}

func (t *ThoughtLearningLinksTool) Link(ctx context.Context, _ *mcp.CallToolRequest, in LinkThoughtLearningInput) (*mcp.CallToolResult, LinkThoughtLearningOutput, error) {
	if err := t.ensureConfigured(); err != nil {
		return nil, LinkThoughtLearningOutput{}, err
	}

	thoughtGUID, err := parseUUID(in.ThoughtID)
	if err != nil {
		return nil, LinkThoughtLearningOutput{}, err
	}
	if in.LearningID <= 0 {
		return nil, LinkThoughtLearningOutput{}, errRequiredField("learning_id")
	}
	relation := strings.TrimSpace(in.Relation)
	if relation == "" {
		relation = "source"
	}

	if _, err := t.store.GetThought(ctx, thoughtGUID); err != nil {
		return nil, LinkThoughtLearningOutput{}, errEntityNotFound("thought", "thought_id", in.ThoughtID)
	}
	if _, err := t.store.GetLearning(ctx, in.LearningID); err != nil {
		return nil, LinkThoughtLearningOutput{}, errEntityNotFound("learning", "learning_id", strconv.FormatInt(in.LearningID, 10))
	}

	if err := t.store.LinkThoughtLearning(ctx, thoughtGUID, in.LearningID, relation); err != nil {
		return nil, LinkThoughtLearningOutput{}, err
	}
	return nil, LinkThoughtLearningOutput{Linked: true}, nil
}

func (t *ThoughtLearningLinksTool) Unlink(ctx context.Context, _ *mcp.CallToolRequest, in UnlinkThoughtLearningInput) (*mcp.CallToolResult, UnlinkThoughtLearningOutput, error) {
	if err := t.ensureConfigured(); err != nil {
		return nil, UnlinkThoughtLearningOutput{}, err
	}

	thoughtGUID, err := parseUUID(in.ThoughtID)
	if err != nil {
		return nil, UnlinkThoughtLearningOutput{}, err
	}
	if in.LearningID <= 0 {
		return nil, UnlinkThoughtLearningOutput{}, errRequiredField("learning_id")
	}

	if err := t.store.UnlinkThoughtLearning(ctx, thoughtGUID, in.LearningID); err != nil {
		return nil, UnlinkThoughtLearningOutput{}, err
	}
	return nil, UnlinkThoughtLearningOutput{Unlinked: true}, nil
}

func (t *ThoughtLearningLinksTool) GetThoughtLearnings(ctx context.Context, _ *mcp.CallToolRequest, in GetThoughtLearningsInput) (*mcp.CallToolResult, GetThoughtLearningsOutput, error) {
	if err := t.ensureConfigured(); err != nil {
		return nil, GetThoughtLearningsOutput{}, err
	}

	thoughtGUID, err := parseUUID(in.ThoughtID)
	if err != nil {
		return nil, GetThoughtLearningsOutput{}, err
	}

	if _, err := t.store.GetThought(ctx, thoughtGUID); err != nil {
		return nil, GetThoughtLearningsOutput{}, errEntityNotFound("thought", "thought_id", in.ThoughtID)
	}

	learnings, err := t.store.GetLinkedLearnings(ctx, thoughtGUID)
	if err != nil {
		return nil, GetThoughtLearningsOutput{}, err
	}
	return nil, GetThoughtLearningsOutput{Learnings: learnings}, nil
}

func (t *ThoughtLearningLinksTool) GetLearningThoughts(ctx context.Context, _ *mcp.CallToolRequest, in GetLearningThoughtsInput) (*mcp.CallToolResult, GetLearningThoughtsOutput, error) {
	if err := t.ensureConfigured(); err != nil {
		return nil, GetLearningThoughtsOutput{}, err
	}

	if in.LearningID <= 0 {
		return nil, GetLearningThoughtsOutput{}, errRequiredField("learning_id")
	}

	if _, err := t.store.GetLearning(ctx, in.LearningID); err != nil {
		return nil, GetLearningThoughtsOutput{}, errEntityNotFound("learning", "learning_id", strconv.FormatInt(in.LearningID, 10))
	}

	thoughts, err := t.store.GetLinkedThoughtsForLearning(ctx, in.LearningID)
	if err != nil {
		return nil, GetLearningThoughtsOutput{}, err
	}
	return nil, GetLearningThoughtsOutput{Thoughts: thoughts}, nil
}

func (t *ThoughtLearningLinksTool) ensureConfigured() error {
	if t == nil || t.store == nil {
		return errInvalidInput("thought learning links tool is not configured")
	}
	return nil
}