package staffing

import (
	"encoding/json"
	"time"

	"github.com/missionworkforce/missionmatch/internal/platform/database/dbgen"
)

// The wire contract for the W3 endpoints. This is the backend interface handoff the future frontend
// consumes; the decision fields mirror slate_members so the existing approve and reject UI carries over.

// GapRequest is the body of POST /recommendations/gap/{requirementID}. Both fields are optional per run
// overrides; the values actually used are recorded in the run's parameters.
type GapRequest struct {
	StaffingFloor      *string `json:"staffing_floor,omitempty"`      // decimal string in [0,100]; default 75
	AdjacencyThreshold *string `json:"adjacency_threshold,omitempty"` // decimal string in [0,2]; default 0.40
}

// PortfolioRequest is the body of POST /recommendations/portfolio. RequirementIDs is an optional explicit
// subset; when empty the portfolio uses ALL open requirements.
type PortfolioRequest struct {
	RequirementIDs     []string `json:"requirement_ids,omitempty"`
	StaffingFloor      *string  `json:"staffing_floor,omitempty"`
	AdjacencyThreshold *string  `json:"adjacency_threshold,omitempty"`
}

// DecisionRequest is the body of POST /recommendations/{recommendationID}/decision.
type DecisionRequest struct {
	Decision string `json:"decision"` // approved | rejected | dismissed
	Note     string `json:"note,omitempty"`
}

// RunView is the run metadata.
type RunView struct {
	ID           string          `json:"id"`
	View         string          `json:"view"`
	ScopeRef     string          `json:"scope_ref,omitempty"`
	ModelVersion string          `json:"model_version"`
	Parameters   json.RawMessage `json:"parameters"`
	CreatedAt    string          `json:"created_at"`
}

// RecommendationView is one recommendation on the wire.
type RecommendationView struct {
	ID              string          `json:"id"`
	RunID           string          `json:"run_id"`
	RequirementID   string          `json:"requirement_id"`
	CandidateID     string          `json:"candidate_id,omitempty"`
	Action          string          `json:"action"`
	Rank            int             `json:"rank"`
	Confidence      string          `json:"confidence"`
	ValueScore      *int64          `json:"value_score,omitempty"`
	Rationale       string          `json:"rationale"`
	RationaleSource string          `json:"rationale_source"`
	Evidence        json.RawMessage `json:"evidence"`
	Status          string          `json:"status"`
	DecidedBy       string          `json:"decided_by,omitempty"`
	DecidedAt       string          `json:"decided_at,omitempty"`
	DecisionNote    string          `json:"decision_note,omitempty"`
	CreatedAt       string          `json:"created_at"`
}

// RunResponse is the generating endpoints' result: the run plus its recommendations in rank order.
type RunResponse struct {
	Run             RunView              `json:"run"`
	Recommendations []RecommendationView `json:"recommendations"`
}

// ProactiveResponse is the bench watch: the current pending proactive recommendations, paginated.
type ProactiveResponse struct {
	Recommendations []RecommendationView `json:"recommendations"`
	Limit           int                  `json:"limit"`
	Offset          int                  `json:"offset"`
}

func runView(r dbgen.RecommendationRun) RunView {
	v := RunView{
		ID:           r.ID.String(),
		View:         r.View,
		ModelVersion: r.ModelVersion,
		Parameters:   json.RawMessage(r.Parameters),
		CreatedAt:    r.CreatedAt.Format(time.RFC3339),
	}
	if r.ScopeRef != nil {
		v.ScopeRef = r.ScopeRef.String()
	}
	if len(v.Parameters) == 0 {
		v.Parameters = json.RawMessage("{}")
	}
	return v
}

func recommendationView(r dbgen.StaffingRecommendation) RecommendationView {
	v := RecommendationView{
		ID:              r.ID.String(),
		RunID:           r.RunID.String(),
		RequirementID:   r.RequirementID.String(),
		Action:          r.Action,
		Rank:            int(r.Rank),
		Confidence:      r.Confidence.String(),
		ValueScore:      r.ValueScore,
		Rationale:       r.Rationale,
		RationaleSource: r.RationaleSource,
		Evidence:        json.RawMessage(r.Evidence),
		Status:          r.Status,
		CreatedAt:       r.CreatedAt.Format(time.RFC3339),
	}
	if r.CandidateID != nil {
		v.CandidateID = r.CandidateID.String()
	}
	if r.DecidedBy != nil {
		v.DecidedBy = r.DecidedBy.String()
	}
	if r.DecidedAt != nil {
		v.DecidedAt = r.DecidedAt.Format(time.RFC3339)
	}
	if r.DecisionNote != nil {
		v.DecisionNote = *r.DecisionNote
	}
	if len(v.Evidence) == 0 {
		v.Evidence = json.RawMessage("{}")
	}
	return v
}

func recommendationViews(rows []dbgen.StaffingRecommendation) []RecommendationView {
	out := make([]RecommendationView, len(rows))
	for i, r := range rows {
		out[i] = recommendationView(r)
	}
	return out
}